My Paper Conservation Internship at the National Postal Museum


By Daisy Todd, NPM Intern and Second year Masters Student of Cultural Materials Conservation at the University of Melbourne

I have just completed a six week paper conservation internship at the Smithsonian's National Postal Museum (NPM). The purpose of the internship was to gain professional experience in the practice of conservation in an industry setting, and to manifest a network of professional contacts in the field of my related specialism. To gain entry into the conservation profession with a MA level qualification, vocational training courses, and multiple internships and fellowships are required. As such I was thrilled that being given the opportunity to work at NPM, as the experience at such an internationally renowned museum would provide an invaluable opportunity for professional development.

The term ‘conservation’ covers all actions aimed at safeguarding cultural property and the objective of the conservation professional is to increase the longevity of this heritage for the benefit of future generations. Conservators are trained to undertake ethically-governed treatment methodologies to effectively mitigate mechanisms of physical and chemical deterioration of museum collections. These conservation treatments customarily include:

  • Visual examination,
  • Technical analysis,
  • Documentation,
  • Remedial treatment, and
  • Preventative care

I find philatelic artifacts fascinating because they are so complex. Philatelic items are normally constituted by a paper substrate which has different types of media applied to it. This media customarily includes gums, inks and adhesive tapes. The interaction of all these different materials makes the conservation of each item very difficult; but also unique. The items are almost like a puzzle that you have to solve before you can undertake any conservation treatment.

When I arrived at NPM (after a 30 hour trip from Australia) I was greeted by Linda Edquist, the head of Preservation. She showed me around behind the scenes of the museum and introduced me to all the staff. She also inducted me into the conservation lab, and assigned me objects out of the collection that needed conservation treatment. The first object that needed conserving was a 1c Statue of Freedom plate proof. Certified plate proofs are the last printed proof of the plate before stamps go into production. This one was from the United States Bureau of Engraving and Printing (BEP). For postal scholars these plates provide important production information in the plate margin inscriptions, including guidelines, plate numbers, and initials of the siderographer, or person who created the plate from a transfer roll. This particular plate proof (Plate 90.) had visible surface and ingrained dirt. The object was gently surface cleaned with grated eraser and a solubility test was performed. Unfortunately many of the hand-written inks were soluble in water which prevented me from carrying out further stain reduction treatments. However the loose fragment was re-attached and the creased top edge reinforced by strip-lining with wheat starch paste (WSP), a conservation grade adhesive that has good aging characteristics and is readily reversible; and Japanese tissue, a long-fibered lignin-free paper.

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1c Statue of Freedom plate proof/ Recto & Verso/ BT & AT

After the success of this treatment, I was then given a set of seven 16c Post Office Clerk plate proofs from the Philippines that were printed in the U.S. The proofs were all in a varying state of disrepair. Overall they were discoloured, with visible staining, and ingrained and surface dirt. Their edges are structurally compromised by tears and skinned areas. The tear folds were embrittled, curling and delaminating. There were visually detracting lacunae (losses) and planar distortions, and the sheets were significantly weakened and fragile to handle.

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16c Post Office Clerk plate proofs/ Recto & Verso/ BT

Each ink on each object was methodically tested and it was concluded that none were soluble. This enabled the following treatments:

  1. Surface cleaning using grated and block vinyl eraser to reduce ingrained and surface dirt.
  2. Humidification to relax the paper facilitating the gentle uncurling of the tear folds.
  3. Aqueous cleaning in deionized water to reduce staining and encourage inter-fibril bonding in the paper sheet.
  4. Deacidification, to pH 9 with calcium hydroxide (1%), to create an alkaline buffer (impeding a common form of paper deterioration known as acid-hydrolysis).
  5. Flattening and drying under felts and planar weights.
  6. Repairing tears and reinforcing skinned and delaminated areas using WSP and Japanese tissue.
  7. Infill lacunae using a toned western paper of equal weight and similar surface texture; which was then adhered with WSP (the reversible, detectable infills homogenized the original aesthetic).
  8. Make chemically inert clear polyester sheaths for each object using an ultrasonic encapsulator.

After treatment each object was structurally stabilized meaning they could be securely handled and studied by postal scholars in the future. The proofs were safely rehoused transported and stored in an environmentally controlled collections storage area.

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16c Post Office Clerk plate proofs/ DT
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16c Post Office Clerk plate proofs/ DT
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16c Post Office Clerk plate proofs/ Recto & Verso/ AT

Another example of the practical treatment that I undertook at the NPM is the revenue stamp essay from the Clarence Henry Eagle Collection. The revenue essay is engraved on very thin printing paper and was attached to an album page with a glassine hinge. There was also a glassine hinge attached to the bottom edge, but its adhesion had failed, enabling the partially detached essay to sharply crease and fold over on itself. There were some planar distortions where the two glassine hinges were applied, with some minor discoloration of the paper, visible from the front. There were also two irregular pieces of discoloured glassine attached to the front margin of the album page.

The glassine hinges were removed mechanically using tweezers, enabling the essay to be detached from the album page. The essay was then gently humidified allowing the fold to be carefully uncurled, realigned and flattened. The crease was then reinforced from the verso with Japanese tissue and WSP. The glassine was removed from the album page margin, and the adhesive residue reduced, using a methyl-cellulose (MC) poultice. The essay was re-attached to the page using a Japanese paper hinge, adhered with WSP.

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Revenue Stamp Essay / Eagle Collection/ Recto/ BT & AT

The NPM also has a magnificent research lab equipped with technical analysis equipment. The research chair at the NPM, Tom Lera allowed me to undertake independent research. I utilized portable x-ray fluorescence spectroscopy (p-XRF) for the elemental analysis of the stamp inks. I was also taught how to use the VSC6000 digital spectral comparator. This machine is popular in the expertization and authentication of philatelic items as it enables their visual examination through the application of different light sources, colorimetry (colour space assessment) and digital microscopy.

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Example of p-XRF spectral analysis
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VSC6000 colorimetry and visual examination

Throughout my time at the NPM I felt welcomed by the staff and equally respected as a colleague. I was invited to attend interdepartmental meetings, and felt privileged to be invited to the Museum Conservation Institute (MCI) to discuss analytical test results. Needless to say, I felt completely spoilt when I was taken on off-site visits to the Conservation Center for Art and Historic Artifacts (CCAHA) and the Barnes Collection in Philadelphia, after I had expressed an interest in going. The NPM is a great host institution for any intern. I felt like I developed professionally and personally during my conservation internship, and am only sad that my 6 weeks went by so quickly!